A tent in the Pinyon Flats campground overlooks the dune field.  Great Sand Dunes National Park and Preserve contains the tallest sand dunes in North America. The Dunefield, topping off with Star Dune at 750 feet, is created by sand trapped by the nearby Sangre de Christo Mountains (larger rougher grains and pebbles) and the San Juan Mountains (65 miles to the west).  Waterways such as Medano Creek help carry the sediment down to the San Luis valley where the dunes are found. Great Sand Dunes National Park and Preserve, Mosca, Colorado.
{}